/**
 * Description:
 * Designer: jack
 * Date: 2018/4/11
 * Version: 1.0.0
 */
public class Coach2 {
    private static Coach2 coach;
    private Coach2(){}

    public  static Coach2 getInstance(){
        if (coach == null) {
            synchronized (Coach2.class) {
                if (coach == null) {
                    coach = new Coach2();
                }
            }
        }
        return coach;
    }
}